1. Field of the invention
This invention relates to a light-sensitive material comprising a light-sensitive layer containing silver halide, a reducing agent, a polymerizable compound and a leuco dye (serving as color image forming substance) provided on a support.
2. Description of prior art
Light-sensitive materials comprising a light-sensitive layer containing silver halide, a reducing agent and a polymerizable compound provided on a support can be used in an image forming method in which a latent image of siliver halide is formed, and then the polymerizable compound is polymerized to form the corresponding image.
Examples of said image forming methods are described in Japanese Patent Publication Nos. 45(1970)-11149 (corresponding to U.S. Pat. No. 3,697,275), 47(1972)-20741 (corresponding to U.S. Pat. No. 3,687,667) and 49(1974) -10697, and Japanese Patent Provisional Publication Nos. 57(1982)-138632, 57(1982)-142638, 57(1982)-176033, 57(1982)-211146 (corresponding to U.S. Pat. No. 4,557,997), 58(1983)-107529 (corresponding to U.S. Pat. No. 4,560,637), 58(1983)-121031 (corresponding to U.S. Pat. No. 4,547,450) and 58(1983)-169143. In these image forming methods, when the exposed silver halide is developed using a developing solution, the polymerizable compound is induced to polymerize in the presence of a reducing agent (which is oxidized) to form a polymer image. Thus, these methods need a wet development process employing a developing solution. Therefore the process takes a relatively long time for the operation.
An improved image forming method employing a dry process is described in Japanese Patent Provisional Publication Nos. 61(1986)-69062 and 61(1986)-73145(the contents of both publications are described in U.S. Pat. No. 4,629,676 and European Patent Provisional Publication No. 0174634A2). In this image forming method, a recording material (i.e., light-sensitive material) comprising a light-sensitive layer containing a light-sensitive silver salt (i.e., silver halide), a reducing agent, a cross-linkable compound (i.e., polymerizable compound) and a binder provided on a support is imagewise exposed to form a latent image, and then the material is heated to polymerize within the area where the latent image of the silver halide has been formed. The above method employing the dry process and the light-sensitive material employable for such method are also described in Japanese Patent Provisional Publication Nos. 61(1986)-183640, 61(1986)-188535 and 61(1986)-228441.
The above-mentioned image forming methods are based on the principle in which the polymerizable compound is polymerized within the area where a latent image of the silver halide has been formed.
Japanese Patent Provisional Publication No. 61(1986) -260241 describes another image forming method in which the polymerizable compound within the area where a latent image of the silver halide has not been formed is polymerized. In the method, when the material is heated, the reducing agent functions as a polymerization inhibitor within the area where a latent image of the silver halide has been formed, and the polymerizable compound within the other area is polymerized.
Further, Japanese Patent Provisional Publication No. 61(1986)-73145 (corresponding to U.S. Pat. No. 4,629,676 and European Patent Provisional Publication No. 0174634A2) describes an embodiment of the image-forming methods, which employs a light-sensitive material comprising a light-sensitive layer containing silver halide, a reducing agent, a polymerizable compound and a color image forming substance provided on a support. The image-forming method comprises: imagewise exposing the light-sensitive material to form a latent image of silver halide; and simultaneously or thereafter developing the light-sensitive material to polymerize the polymerizable compound, and thereby fixing the color image forming substance on the support within the area where the polymerizable compound has been polymerized.
An example of the color image forming substance employable for the above-mentioned image-forming method is a leuco dye, which is also called a redox dye. The leuco dye can develop to give a color in contact with an acid color developer. These leuco dyes have been mainly used in a pressure sensitive paper or a heat sensitive paper.